Iron sponge containing prereduced iron ore is pelletized into pellets which are melted by the pellets being fed to an iron melt in the hearth of an electric arc furnace conventionally constructed with the typical cylindrical shape and having one or more centrally psoitioned arcing electrodes. The arc or arcs formed between the electrodes and the melt may be powered by either AC or DC.
The pellets, fed through one or more feeders in the furnace roof, sometimes fall on the melt at positions remote from the arc or arcs even though aimed at the latter. When this happens, the pellets floating on the melt tend to form a crust and to become oxidized, or in effect reoxidized, which interferes with the desired rapid melting of the pellets. Usually there is a slag layer floating on the melt. The arc or arcs drive this slag radially outwardly to expose the melt centrally within the furnace, which is desirable because it permits the pellets to fall on clean molten metal if the pellets go where they are aimed. This action of the arc or arcs has the undesirable effect of not only driving away the slag, but also the pellets, not only resulting in the problem of the crust formation and oxidation or reoxidation of the pellets, but also having the undesirable effect of producing a thickened slag layer at the furnace's slag line and thus increasing the normal attack of the slag on the furnace wall lining.
In addition to these troubles, the slag layer is thinned centrally around the arc or arcs, thus exposing the furnace wall lining to direct radiation from the arc or arcs, to an undesirable degree.
Electric arc furnaces have been provided with electric inductive stirrers positioned below the bottom of the hearth, the hearth being made with a non-magnetic construction. Such a stirrer is in the form of a flat coil or coils which can be powered with multiphase AC to inductively stir the melt in the hearth. Such stirrers have been ineffective insofar as any correction of the above described troubles is concerned.